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APOGEE Apache Point Observatory Galactic Evolution Experiment

APOGEE is an infrared, high-resolution spectroscopic survey of the stellar populations of the Galaxy, aiming to map the chemical evolution, kinematics, and structure. This endeavor probes the 3-D chemical abundance distribution, metallicity gradients, and Galactic rotation curve, among other broad science goals. The survey utilizes cryogenic spectrographs to study molecular and atomic features in stars near the tip of the giant branch across various Galactic populations.

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APOGEE Apache Point Observatory Galactic Evolution Experiment

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  1. APOGEE Apache Point ObservatoryGalactic Evolution Experiment Matthew Shetrone

  2. SDSS-III http://www.sdss3.org APOGEE: an infrared, high resolution spectroscopic survey of the stellar populations of the Galaxy BOSS: will measure the cosmic distance scale via clustering in the large-scale galaxy distribution and the Lyman-α forest SEGUE-2: will map the structure, kinematics, and chemical evolution of the outer Milky Way disk and halo MARVELS: will probe the population of giant planets via radial velocity monitoring of 11,000 stars

  3. APOGEE at a glance • Bright time SDSS-III survey, 2011.Q2 to 2014.Q2 • 300 fiber, R ≈ 22,500, cryogenic spectrograph, 7 deg2 FOV • H-band: 1510 – 1690 nm (AH /AV ~ 1/6) • Typical S/N = 100/pixel@ H=12.2 for 3-hr integration • RV uncertainty < 100 m/s in 1hr • 0.1 dex precision abundances for ≈ 15 chemical elements (including C, N, O, Fe, other α, odd-Z, possibly neutron-capture) • 105 2MASS-selected [(J-K) > 0.5] predominantly giant stars, probing all Galactic populations

  4. The Spectra

  5. The Spectra

  6. The Spectra

  7. Unblended Lines in H band? Molecules are very prevalent in the H-band: CO, CN, OH in addition to the atomic features: Mg, Fe

  8. The Spectra A small piece of the APOGEE specta for stars near the tip of the giant branch in several GC. OH is visible even in the most metal-poor clusters but the double metal molecules disapear quickly with decreasing metallicity.

  9. Broad Science Goals • A 3-D chemical abundance distribution(many elements), MDFs across Galactic disk, bar, bulge, halo. • Probe correlations between chemistry and kinematics(note Gaia proper motions eventually as well). • Constrain SFH and IMF of bulge/disk as function of radius, metallicity/age, chemical evolution of inner Galaxy. • Detailed study of Galactic bar and spiral arms and their influence on abundances/kinematics of disk/bulge stars. • Measure Galactic rotation curve (include spec. p., Gaia pm) • Search for and probe chemistry/kinematics of (low-latitude) halo substructure(e.g., Monoceros Ring). • Combine with existing/expected optical, NIR and MIR data and map Galactic dust distributionusing spec. p’s, constrain variations in extinction law • Look for early generations of stars and/or their signatures in the chemistry of the most metal-poor bulge stars

  10. Current Field Plan Field Center Plan: 24 hour 12 hour 3 hour (science) 3 hour (calibration) 1 hour ~343 fields ~600 star clusters ~116,000 science stars including Kepler fields

  11. Ongoing Effort • Some half dozen technical papers in progress. • Several science papers in progress, some published • DR10: First APOGEE data release (summer 2013). • All “Year 1” (May 2011-July 2012) data • Targeting & suppl. data (e.g., photometry, proper motions, cat. source) • Extracted, calibrated 1-D spectra • RVs, RV variability, v sin i • Teff, log g, ξ, [Fe/H], [α/Fe], C, N • DR12: Last APOGEE I data release (December 2014) • All APOGEE 1 (May 2011 – July 2014) data • Stellar parameters and velocities as in DR10 • Individual elemental abundances (Si, Ca, Al, V, etc..)

  12. APOKASC? Early Science Highlights • Stellar ages from the APOKASC (Epstein/Pinnsoneault et al.) • To date, ~2800 Kepler stars (mostly asteroseismology giants) observed by APOGEE.

  13. Early Science Highlights • Detection of high velocity stars in Galactic bulge/bar(Nidever/Zasowski et al. 2012) Seem to be a family of stars on leading edge of bar. If this interpretation is correct, a negative RV counterpart should be found in the IV quadrant

  14. Early Science Highlights • Metallicity gradients in the disk (Holtzman/Hayden et al.) • Distances from ASPCAP + RJCE dereddenings.

  15. Early Science Highlights • Improving knowledge about open clusters (Frinchaboy et al.)

  16. Early Science Highlights • Be stars found among telluric standards (Chojnowski et al.) Brackett Line Emission

  17. Your Free Access • Basic Searches: There are two basic ways to make a search for APOGEE results: 1) From the SDSS-III DR10 Catalog Archive Server (CAS or SkyServer) http://skyserver.sdss3.org/dr10/en/home.aspx or 2) From the DR10 Science Archive Server (SAS) http://dr10.sdss3.org/basicIRSpectra. The SAS is what you might use if you want the actual spectra, while the SkyServer is useful for making lists of targets or data results. Below we show how one might search for targets in a cluster and then retrieve a spectrum of a cluster star: • CAS SkyServer Example Query • http://skyserver.sdss3.org/dr10/en/tools/search/IRQS.aspx The query produces the following on a web page

  18. SAS Example Query http://dr10.sdss3.org/basicIRSpectra Coping one id into SAS server The query produces the following on a web page

  19. Observing the Central Milky Waywith APOGEE+Sloan 2.5-m From Apache Point Observatory: Galactic center culmination @ altitude = 28˚ (airmass = 2.1!) Sky above 2 airmasses:Apache Point ObservatoryLas Campanas Observatory

  20. Extending APOGEE • SDSS3/APOGEE Survey ends July 2014 • SDSS3: Resulting 105 sample very large, but still scratching surface: • Halo sample relatively shallow. Chance to go deep. • Bulge currently relatively “meagerly” sampled (~8,000 stars). • Bulge, bar and inner disk hard to do from APO!! • high airmass reduces FOV due to differential refraction effects • only partial bulge coverage • pile-up of inner Galaxy longitudes over small range of RA • APOGEE extension for “After Sloan-III”: • APOGEE-2North significantly increase sample by factor of several. • Instrument ready from the start – ideally another ~250,000 stars. • APOGEE-2South, cloned instrument on Du Pont 2.5-m at LCO • 100,000 – 170,000 stars.

  21. Science of an APOGEE-2North • Significantly increase halo, thick disk outer disk samples. • Substantially boost overall statistics, observing from Day 1. • Opportunity for increasing time series work. • stellar and substellar companions leveraging RV precision. • both 1-m dark time & 2.5-m bright time operations continue. • Expand extremely useful synergy with Kepler mission. • 10 visits per tile. • increase asteroseismology sample. • characterize planet/non-planet hosts. • robustly assess Kepler false alarm rate. • dynamical masses from eclipsing binaries. • continue contributing tofundamental astrophysics.

  22. Science of an APOGEE-2South • Large chemical and kinematical study of the Galactic bulge • 65,000-100,000 stars (or more) & ~15 elements • Significantly increase sampling of low end of MDF. • Increase chance of seeing “first” stars (Tumlinson 2010) …...or constrain their nature from abundance imprint on succeeding generations (Eckstroem et al. ‘08). • X-shaped bulge (McWilliam & Zoccali 2010, De Propris et al. 2011). • Star formation, clusters & history of Galactic center environment. • Sample other rare stellar types. (e.g., C-stars, CN-strong stars, S-type, Mira, very young stars) • Center of halo and disk distributions. • Explore dynamics of the bar(s). Fulbright et al. 2007: ”The notion of a bulge that formed early, and rapidly, remains attractive. This conclusion is consistent with observations of galaxy formation at high redshift. However, itremains vital to study additional elements and larger samples of stars because the fossil record locked in the bulge's composition has the potential to provide a detailed record of its history that is unmatched by anything that can be inferred from the observations of distant galaxies."

  23. Science of an APOGEE-2South • Significant/homogeneous surveys of 4 other Local Group galaxies: • Large and Small Magellanic Clouds, Sagittarius, ω Centauri • Halo/disk substructure and (as)symmetries • Disk/bar/spiral arm symmetry by inclusion of III and IV quadrants. • Clear views of Monoceros/Canis Major/Argo (warp or tidal stream?). • Disk warp and disk edge/truncation. • Far side of the disk, beyond bulge. • Follow-up for southern hemisphere photometric surveys (VVV and SkyMapper). • Star cluster chemistry (85% lie below celestial equator) • Metal-rich bulge/disk clusters study (not possible in north). • Important targets: e.g., 47 Tuc, NGC 288/362, N6338/N6441, NGC 6528, 6533, Sgr & Magellanic clusters. • Integrated light in Magellanic clusters.

  24. APOGEE-2 Sky Coverage Approaching half million stars in combined APOGEE-1 & -2.

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